It is basically a 6 point star. This ruler by Jan Krentz would be what I would use to recreate a similar look.
https://www.jankrentz.com/weblog/wp-.../01/10455A.jpg
When you look at the star as a closeup, it is split down the center, therefore no y seams. Jan's rulers have the divisions on them to be able to strip piece all the diamonds.